How can I render an image with sharp and uniform color edges?
It has been a while, but IIRC the method to get pixel precision is via our output resolution and the scale of your objects.

For example, if your resolution is 1920x1080, you can create a pixel precise plane if you set the plane's dimensions to 1.920 and 1.080. Note that if you use larger scales, your images will suffer from cubic interpolation that will degrade any textures you place on them.

An orthographic camera should flatten the perspectival transform to be pixel perfect.